The EU’s chief negotiator, Michel Barnier, has warned that Brussels will not rely on Michael Gove’s pledges over the environment but instead insist on a “non-regression” clause in any future deal after Brexit to tie the UK to the bloc’s high standards.

Barnier said he welcomed a 25-year plan published in January by the environment secretary, a fervent Brexiter during the referendum campaign, under which the UK vowed to be a “global champion” of greener policies after 29 March 2019.

But Barnier said in a debate in the European parliament on Tuesday that the 27 member states would be “extremely vigilant” in blocking any attempt by the British government to undercut current regulations to gain a competitive advantage.

The future partnership with the UK “should include a non-regression clause and prevent the reduction of pre-Brexit standards”, the former French minister said. “If we make sure our partnership is based on a level playing field … then we should have strongly mitigated the threat of Brexit to EU environmental policy,” he told MEPs. “There will be no ambitions partnership without guarantees on fair competition, social standards, tax dumping and not least environmental standards.”

A coalition of the UK’s leading environmental groups says there is a “significant risk” that British environmental protections will be reduced after Brexit, despite the government’s positive rhetoric. EURACTIV’s partner The Guardian reports.

Gove and the foreign secretary, Boris Johnson, have previously counselled Theresa May that the UK will only be able to reap the advantages of Brexit if the UK diverges from the EU in terms of its regulatory standards in some key sectors. However, the environment secretary has also insisted that the UK will “occupy the high ground” on green standards.

Barnier said he hoped that Gove’s position would translate into the negotiation over the coming months, as the UK spells out how it intends a future trade deal to work.

He said: “Does the UK want to stay close to European regulatory model or distance itself from it?

“It’s a very important question because European regulatory model is underpinned by choices that are very dear to us.

“What we hear from the UK could be seen as reassuring … This is reflected in the UK’s proposed 25-year plan on the environment. This is welcome but my responsibility as EU’s lead negotiator is to remain extremely vigilant.”

Barnier added that he expected agreement on a non-regression clause to be difficult, and that he would want its scope to widen anything seen before. “We know Britain wants to integrate all existing standards in law,” he said, “but what happens on day plus-10?

“Currently the UK is totally integrated but we are going to diverge. What will become of this divergence? Does it remain reasonable? Or does it become a tool for social, fiscal and environmental dumping? We face a huge risk of ratification from national parliaments if we don’t reassure people and provide solutions.”

In an illustration of his intention to raise standards, Gove is consulting on a ban on the export of live animals. The National Farmers’ Union estimates up to 20,000 live sheep were exported to Europe in 2017.

EU single market legislation currently prevents the UK from prohibiting exports of livestock.

On top of weakening environmental protection in the UK, a hard Brexit would strengthen the influence of the EU’s climate sceptic governments and undermine the bloc’s commitments at home and abroad, writes Joseph Curtin.